The president of the National Audubon Society visited the mountain slopes of Haleakala on Maui Thursday to bring attention to a critical opportunity to preserve endangered Hawaii birds.

"Hawaii is really America’s hot spot for endangered birds, and there’s such an opportunity to protect them," said society President David Yarnold. "It’s certainly not too late."

Yarnold and nearly a dozen other people participated in the society’s annual Christmas bird count, the longest running and largest animal counting activity in the world.

An estimated 70,000 people nationwide participated in the event this year.

Along trails near Hosmer’s Grove, the volunteer group saw about 160 birds in a couple of hours, including nine different species — about the same as last year, Yarnold said.

In two hours, most sightings included 23 iiwi, 39 apapane and 40 amakihi, the society said.

Yarnold said about half of the endangered bird species in the United States live in Hawaii.

He said major factors reducing native bird populations include development that fragments their habitat and global warming, which increases the upland range of mosquitoes and the spread of avian malaria.

He said avian malaria has harmed the populations of Hawaiian crows, honeycreepers and iiwi.

Yarnold said some places lack fencing to keep out invasive species, including wild pigs, as called for under federal wildlife habitat restoration plans.

"The safety for bird species hasn’t been properly enforced," he said.

He said pig wallows are breeding grounds for avian malaria.